Semantic Web

The Semantic Web is a vision of the future of the World Wide Web proposed by Tim Berners-Lee consisting of documents that are put together in such a way that it facilitates automated information gathering and research in a far more meaningful way than can be accomplished with current web search tools.

The usability and usefulness of the Web and its interconnected resources will be enhanced through:

• documents 'marked up' with semantic information (an extension of the <meta> tags used in today's Web pages to supply information for Web search engines using web crawlers). This could be machine-readable information about the human-readable content of the document (such as the creator, title, description, etc of the document) or it could be purely metadata representing a set of facts (such as resources and services elsewhere in the site).
  (Note that anything that can be identified with a Universal Resource Identifier (URI) can be described, so the semantic web can reason about people, places, ideas, cats etc.)
• common metadata vocabularies (ontologies) and maps between vocabularies that allow document creators to know how to mark up their documents so that agents[?] can use the information in the supplied metadata (so that Author in the sense of 'the Author of the page' won't be confused with Author in the sense of a book that is the subject of a book review).
• automated agents to perform tasks for users of the Semantic Web using this metadata
• web-based services (often with agents of their own) to supply information specifically to agents (for example, a Trust service that an agent could ask if some online store has a history of poor service or spamming).

The primary facilitators of this technology are: URIs (which identify resources) along with XML and Namespaces. These, together with a bit of logic form RDF, which can be used to say anything about anything. As well as RDF, many other technologies such as Topic Maps and pre-web AI technologies are likely to contribute to the Semantic Web.

All current web technologies are likely to have a role in the semantic web (in the sense of semantic world wide web), for instance :

• DOM The Document Object Model which provides a set of standard interfaces for accessing XML and HTML document components.
• XPath, Xlink[?], XPointer
• XInclude[?] XML fragment[?] XML query language XHTML
• RDF (Resource Description Framework)
• XSL, XSLT Extensible Stylesheet Language
• SVG (Scalable Vector Graphic)
• SMIL
• SOAP
• DTD
• the concept of metadata.

You can create a piece of RDF code to describe yourself to the Semantic Web using the Friend-of-a-Friend-o-matic (http://www.ldodds.com/foaf/foaf-a-matic.html)

See also:

• W3C
• Topic maps
• Dublin Core
• WordNet
• DAML+OIL
• Cyc
• Knowledge representation
• Knowledge technologies
• OWL

External links

• W3C Semantic Web initiative (http://www.w3.org/2001/sw/)
• Tim Berners-Lee's 1998 roadmap paper (http://www.w3.org/DesignIssues/Semantic.html)
• Scientific American article on The Semantic Web (http://www.sciam.com/2001/0501issue/0501berners-lee.html)
• Semantic Web Community Portal (http://www.semanticweb.org/)